埃塞俄比亚的中央高地房屋建筑木材消费和树种偏好-提高树木种植的意义

2008年间在埃塞俄比亚高原调查房屋建筑木材消费和树种偏好情况,以及森林产品建设的策略和未来利用的可能性。对36座农家住户其中包括24座铁皮屋顶的房子和28座茅草盖顶的房子为对象进行调查,研究建筑木材的种类、材积和来源。结果表明,平均一座房屋的每57m^2地面空间面积需消耗木材13．7m^3。地面空间面积和木材消耗量的变化随房屋种类而变化。平均一座铁皮屋顶的房屋的每51．9m^2地面空间面积需消耗木材16．8m^3,平均一座茅草盖顶的屋顶每286m2地面空间面积需消耗木材3．2m^3。家庭和地面空间面积的大小是影响建筑木材消耗的主要因素。平均一座住房需消耗木材种类分别为,9．3％非洲铅笔柏（Juniperus procera）、5．6％墨西哥落羽杉（Cupressus Iusitanica）、29．2％蓝桉（Eucalyptus globulus）和26％赤桉（Eucalyptus camaldulensis）。由非洲铅笔柏（Juniperus procera）,墨西哥落羽杉和蓝桉来源的木材被限制。因此,目前木材短缺大约为59．5％。建议改进树木的种植方法来提高木材量,同时可研制土壤砖当作建筑材料的替代品。     

Phosphorus Fractions in Sodic Soils of the Great Ethiopian Rift Valley Soils as Affected by Reclamation

Soil phosphorus (P) availability is commonly assumed to limit productivity in tropical soils, yet there is relatively little information on the chemical forms of soil P in such ecosystems. The study was conducted to determine the size P pools via application of gypsum. We used a sequential fractionation to assess P fractions. The average total P concentration was 519 mg kg?1. Soil organic P was relatively low (74 mg kg?1). The ratio of organic carbon to organic P was generally greater than 298, suggesting the potential for immobilization. Calcium-associated P was the dominant inorganic P pool, whereas Al+Fe-P was the second dominant. Readily available P was very low (1.3 mg kg?1). Gypsum at different level was used as a reclamation material for sodic soils, and application of gypsum significantly affected the different P fractions. Organic P forms were significantly lower for higher levels of gypsum application.     

Estimation of genetic parameters for growth traits and Kleiber ratios in Boer x Central Highland goat

Tropical Animal Health and Production - Accurate performance evaluation and genetic parameters estimation are the prerequisites for any successful genetic improvement program. This study was...     

Variation and inheritance of erucic acid content in Brassica carinata germplasm collections from Ethiopia

Ethiopian mustard possesses a number of agronomic advantages over other oilseed crops with similar ecological adaptation in Ethiopia. However, its high erucic acid content is undesirable for a vegetable oil. Although efforts have been made to improve its quality, much has to be done to use natural variations that might exist within the species for fatty acid contents. This project was undertaken to study the variability of fatty acid contents, primarily erucic acid, in germplasm collections of Ethiopian origin, with an attempt to develop low (zero) erucic acid genotypes. The study used inbred lines as well as F₂ populations of 10 crosses between six parental lines. A wide variation in fatty acids was found. Oleic acid content varied from 5 to 34% and erucic acid content from 6 to 51%. Linoleic and linolenic acid contents were less variable. The high‐oleic genotypes exhibited not only low erucic but also higher linoleic (25%) and considerably lower linolenic acid (8%) contents. It was possible to classify the F₂ populations with the lowest erucic acid into three distinct classes. While the first class had an erucic acid content of 6–12%, the second and third classes had contents of 18–32% and 36–42%, respectively. The existence of a multiple allelic series of erucic acid in Ethiopian mustard would enable its fixation at zero levels without necessarily going into interspecific crossing.     

Performance and limitation of two dairy production systems in the North western Ethiopian highlands

In order to characterise the dairy production systems as well as the productive and reproductive performance of dairy cows in the study area, a total of 256 and 54 dairy farms were used for survey and monitoring data collection, respectively. Based on breed, land size, feed and market accessibility, two major dairy production systems were identified: a rather specialized, urban, and a peri-urban dairy production system. Urban farmers owned larger herds but farmed less land, and sold a greater proportion of liquid milk than peri-urban farmers, who processed more milk. Purchased feed played a more important role for the feed supply of urban than peri-urban farms. Significant breed effects were found for productive and reproductive performance traits. It is concluded that improved breeding and health management, genetic improvement of local breeds and supplementation of poor quality feed resources are the key factors for enhancing productivity of dairy cows and thereby increasing family income from milk production.